Mainline version history question

Rossputin · 4996

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Offline Rossputin

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on: January 28, 2023, 11:10:27 AM
Hello all,

I assume that version 1.1 of the main line is some kind of upgrade or update over the original.

First question: is that correct or was the first one called 1.1?

Second: If it is correct, is there a place where I can see what the changes were between the original and the 1.1?

Finally: What's your opinion about the relative value of the two if I am looking to buy a preowned one?

Thanks in advance for any help!



Offline Paul Birkeland

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Reply #1 on: January 28, 2023, 11:53:34 AM
The 1.1 update allowed us to substitute the separate 120V and 240V power transformers with one part that could be wired for those voltages and several others.  We also slightly tweaked the power supply PC board and took the opportunity to update those build photos to reflect using leaded capacitors rather than the older snap-in caps. 

Otherwise the rest of the build is the same.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rossputin

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Reply #2 on: January 28, 2023, 12:20:28 PM
Thanks, Paul, that's VERY interesting.

If I buy one of the originals I will listen for a good amount of time before considering any mods and I know you've said on the forum in the past that the Mainline really isn't a product that wants/needs many mods or upgrades but my question for you is: if you had version 1.0 with no upgrades what, if anything, would you update/upgrade?

Thanks again!
Ross in Denver
(Crack/Speedball owner right now, probably moving to Mainline as I get some high-end headphones)



Offline Paul Birkeland

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Reply #3 on: January 28, 2023, 05:50:08 PM
You could swap out the 10uF parallel feed caps for some 20uF V-cap ODAMs.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rossputin

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Reply #4 on: January 30, 2023, 12:46:44 PM
OK, and is it obvious in the manual or elsewhere which are those caps that you're saying I can upgrade? Or possible for you to post a picture with the specific cap circled?



Offline Rossputin

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Reply #5 on: January 30, 2023, 12:52:18 PM
Hi Paul,

Looks like V-Cap ODAM come in 18uf and 22uf.

Which would you use, and are there other caps that you think are nearly as good but a lot less expensive?

Thanks again!



Offline Paul Birkeland

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Reply #6 on: January 30, 2023, 03:40:17 PM
Not particularly.  If you're going through the trouble and upgrading about the only parts in the amp that can be swapped out, go big!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rossputin

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Reply #7 on: January 30, 2023, 06:41:32 PM
I like that philosophy. Can you help me make sure I'm looking at the right parts to swap? Are they the big 10uf Dayton film caps just forward of the OT-3 transformers on each side? And should I go with 18uf or 22uf in V-Cap? Are V-Cap that much better than the various Mundorf lines? I REALLY appreciate your input, Paul!

By the way, I talked about Bottlehead products on my radio show today!



Offline Paul Birkeland

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Reply #8 on: January 30, 2023, 06:51:53 PM
Either 18uF or 22uF, whichever suits your fancy.  Yes, they replace the 10uF caps.

The Mundorfs that would make sense for the circuit are oddly shaped and aren't likely to fit all that well.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rossputin

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Reply #9 on: January 31, 2023, 04:04:58 AM
Hey Paul, I haven't checked the physical dimensions yet as far as fitting in the Mainline but other than that what do you think of these? (They're 50% off right now...much cheaper than ODAM at the moment.)
https://www.v-cap.com/oil-capacitors.php




Offline Paul Birkeland

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Reply #10 on: January 31, 2023, 04:25:10 AM
The voltage rating is insufficient.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Rossputin

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Reply #11 on: January 31, 2023, 09:16:36 AM
gotcha...what's minimum voltage rating we need?



Offline Thermioniclife

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Reply #12 on: January 31, 2023, 09:24:14 AM
250v or higher.

Lee R.


Offline Rossputin

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Reply #13 on: February 07, 2023, 11:09:17 AM
OK, one more cap question: Opinion of Clarity Cap CMR (I know they're large) vs VCap ODAM?



Offline Paul Birkeland

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Reply #14 on: February 07, 2023, 12:42:44 PM
Way too big to fit the space.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man